A few thoughts on finishing...are you planning to use the West Mirror Coat? It's good stuff, but the challenge I have found with epoxy is that it's relatively unforgiving with witness lines. Like polyurethane, it builds in successful coats rather than melting together - but I haven't been able to buff out witness lines in epoxy like I've been able to do with some of the better varnish blends. You sand too low in one area, your only solution is to recoat and try again.
The claro walnut bass in my avatar was finished with General Finishes Arm-R-Seal (another oil/urethane blend), and that stuff buffed up nicely to a warm semi-gloss as well as the Behlen's. I also did a couple recent instruments with Benjamin Moore clear gloss varnish, but the retailer near me stopped carrying it and I had to find some alternatives.
My advice, try the Behlen's if you can find it. Pour an equal amount of varnish and mineral spirits (easily procured in the paint section at Lowes and Home Depot) into a tupperware type container with a sealing top. Add a couple drops of Japan Drier (also available in the paint section). Stir carefully to evenly mix the thicker varnish with the thinner.
Then, using brush labeled for varnish and oil-based finished, apply about three or four smooth, drip-free coats. There's a technique called tipping off that takes a little practice to help get your coats to lay down evenly (google it and you can read up). After your third or fourth coat, you'll see the finish starting to build in some areas and not in others. This is normal.
Give it a light sanding with 320 all over the body, blast it with some compressed air, and apply another three or four coats.
Repeat 4x.
After about 12 to 15 coats, you should have a hard film finish over the entire instrument that is hopefully drip-free and relatively even looking. Don't go crazy if there are sags or defects, they can all be sanded out once cured.
Wait three weeks. Maybe four.
I can walk you through the sanding and polishing process to get the high gloss look you mentioned going after.